1. Field of the Invention
The present invention relates to a capacitor.
2. Related Background Art
In general, capacitor devices used in capacitors such as electrolytic capacitor are made by the steps of using a metal such as aluminum, titanium, or tantalum (so-called valve metal) having a capability of forming an insulating oxidized film as an anode; anode-oxidizing a surface of the valve metal, so as to form an insulating oxidized film; thereafter forming a solid electrolyte layer made of an organic compound or the like substantially functioning as a cathode; and further providing a conductive layer such as graphite or silver as a cathode.
Known as methods of lowering the impedance of such capacitors include those lowering equivalent series inductance (ESL) and equivalent series resistance (ESR). Japanese Patent Application Laid-Open No. 2001-102252 discloses a capacitor which omits a lead frame in order to reduce the ESR. The capacitor disclosed in the above-mentioned publication is one including a substrate having a device mounting surface on which a double terminal type capacitor device having a pair of electrodes is mounted, whereas the electrodes on the device mounting surface of the substrate are connected to electrodes on the rear face thereof via through holes.
Here, a mounting substrate on which the capacitor is mounted is provided with two kinds of terminals, i.e., anode and cathode electrode terminals. When the capacitor is of multiterminal type, the anode and cathode electrode terminals are arranged in a row while alternating with each other in general. Therefore, anode and cathode outer connecting terminals corresponding to the anode and cathode electrode terminals, respectively, are arranged in a row while alternating with each other on the surface of the substrate opposite from the device mounting surface. When the above-mentioned through holes are simply employed in this substrate, anode electrode patterns connected to the anode outer connecting terminals by way of the through holes and cathode electrode patterns connected to the cathode outer connecting terminals by way of the through holes are arranged in a row while alternating with each other on the device mounting surface of the substrate, whereas their row is oriented in the same direction as with the row of the anode and cathode outer connecting terminals on the opposite surface.
The workability at the time of connecting anode parts of capacitor devices improves as the area of anode electrode patterns formed on the device mounting surface of the substrate increases. Also, the area usable for connecting with the anode parts of capacitor devices can be increased, whereby the connecting strength can be improved.
However, the above-mentioned conventional capacitor device has been problematic in that it does not sufficiently improve the workability at the time of connecting capacitor devices to the substrate and the connecting strength therebetween, since the anode electrode patterns are small.
Therefore, in order to overcome the problem mentioned above, it is an object of the present invention to provide a capacitor in which anode electrode patterns of the substrate are enlarged.